Technical Field
The present disclosure relates to an armature of a rotating electric machine, and more particularly, to an armature of a rotating electric machine with improved wedges.
Background Art
Generally, an electric machine is an energy conversion machine that converts electrical energy into mechanical energy or mechanical energy into electrical energy, such as a rotating electric machine that includes a motor and a generator. Recently, various types of rotating electric machines have been developed to increase efficiency and power density. A vehicle also includes a plurality of motors and generators. For example, an electric vehicle, a hybrid electric vehicle, and a fuel cell vehicle, which are eco-friendly vehicles, include a driving motor as a power source for driving, and the other vehicles use various types of motors, such as actuators for various machines.
As is well-known in the art, a rotating electric machine has a stator and a rotor, wherein the stator includes a core and a permanent magnet attached on or embedded within the core, and the rotor includes a core and coils wound (e.g., wrapped) around slots of the core. However, the above-described configuration is only exemplary. In other words, coils may be wound around the stator, instead of the rotor, and the permanent magnet may also be attached on the rotor, instead of the stator. In addition, in a wound rotor synchronous motor (WRSM), both a rotor and a stator have coil windings. In a rotating electric machine, a stator or a rotor around which coils are wound is called an armature, and in the following description, a rotor core or a stator core around which coils are wound through slots will be referred to as an armature core.
Further, in an armature of a rotating electric machine, wedges are used to fix and support the positions of coils wound around slots and to prevent the coils from seceding from the armature. The wedges are disposed within the slots around which the coils are wound within an armature core or the openings of the slots, to fix and support the coils and to prevent the coils from seceding from the armature core. However, wedges of the related art may decrease assembly efficiency since wedges are inserted in the axial direction through openings and assembled after coils are wound around stator slots of a motor. In addition, wedges of the related art have a complex configuration and require a complex assembly process, which may result in an increased weight and manufacturing costs.
FIG. 1 is an exemplary cross-sectional view showing an example of an armature in which wedges with a simple structure are installed according to the related art. In FIG. 1, a wedge 15 is disposed within a slot 12 of a rotor core 10 in a WRSM of a hybrid electric vehicle. As shown in FIG. 1, the wedge 15 assembled within the slot 12 of the core 10 closes an opening 12a of the slot 12, and supports and fixes coils 14 disposed to a left side and a right side of the slot 12 to prevent the coils 14 from seceding (e.g., separate) from the core 10. The wedge 15 is fabricated of a plastic material, and after coils 14 are wound around the slot 12 of the rotor core 10, the wedge 15 is inserted into the slot 12 in the axis direction of the rotor core 10 and assembled.
However, since the wedge 15 is fabricated with a plastic material, the wedge 15 may lack stiffness and durability. In addition, since the wedge 15 is inserted into the slot 12 in the axial direction and assembled, the wedge 15 may be difficult to assemble. In other words, when the wedge 15 is inserted into the slot 12 in the axial direction of the core 10 and the wound coils 14 within the slot 12 swell (e.g., enlarge) or the wound coils 14 protrude into the slot 12, the wedge 15 may get caught on the coils 14 (e.g., the coils 14 interfere with the insertion of the wedge) to prevent the wedge 15 from being inserted into the slot 12, and great power may be required to insert the wedge 15 into the slot 12. Further, when the wedge 15 is inserted in the axial direction, the wedge 15 may need to be inserted carefully into the slot 12 to prevent the wedge 15 from being caught by the coils 14 within the narrow space of the slot 12.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.